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Previous issue date: 2011-10-27 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Discussions about pollution caused by vehicles emission are old and have been developed
along the years. The search for cleaner technologies and frequent weather alterations have
been inducing industries and government organizations to impose limits much more rigorous
to the contaminant content in fuels, which have an direct impact in atmospheric emissions.
Nowadays, the quality of fuels, in relation to the sulfur content, is carried out through the
process of hydrodesulfurization. Adsorption processes also represent an interesting alternative
route to the removal of sulfur content. Both processes are simpler and operate to atmospheric
temperatures and pressures. This work studies the synthesis and characterization of
aluminophosphate impregnate with zinc, molybdenum or both, and its application in the
sulfur removal from the gasoline through the adsorption process, using a pattern gasoline
containing isooctane and thiophene. The adsorbents were characterized by x-ray diffraction,
differential thermal analysis (DTG), x-ray fluorescence and scanning electron microscopy
(SEM). The specific area, volume and pore diameter were determined by BET (Brunauer-
Emmet-Teller) and the t-plot method. The sulfur was quantified by elementary analysis using
ANTEK 9000 NS. The adsorption process was evaluated as function of the temperature
variation and initial sulfur content through the adsorption isotherm and its thermodynamic
parameters. The parameters of entropy (ΔS), enthalpy variation (ΔH) and free Gibbs energy
(ΔG) were calculated through the graph ln(Kd) versus 1/T. Langmuir, Freundlich and
Langmuir-Freundlich models were adjusted to the experimental data, and the last one had
presented better results. The thermodynamic tests were accomplished in different
temperatures, such as 30, 40 and 50?C, where it was concluded the adsorption process is
spontaneous and exothermic. The kinetic of adsorption was studied by 24 h and it showed that
the capability adsorption to the adsorbents studied respect the following order: MoZnPO >
MoPO > ZnPO > AlPO. The maximum adsorption capacity was 4.91 mg/g for MoZnPO with
an adsorption efficiency of 49%. / As discuss?es sobre o problema da polui??o causada por emiss?es veiculares s?o
antigas e v?m evoluindo com o passar do tempo. A procura por tecnologias mais limpas e as
altera??es clim?ticas cada vez mais frequentes induziram as ind?strias e os ?rg?os
governamentais a impor limites cada vez mais rigorosos para os teores de contaminantes nos
combust?veis, os quais impactam diretamente nas emiss?es atmosf?ricas. Atualmente a forma
de melhorar a qualidade dos combust?veis, quanto ao enxofre, ? atrav?s do processo de
hidrodessulfuriza??o e recentemente, os processos de adsor??o tem se mostrado como uma
alternativa bastante interessante ? remo??o de enxofre, pois tais processos s?o mais simples e
operam a temperaturas e press?es atmosf?ricas. O presente trabalho contempla a s?ntese e
caracteriza??o do aluminofosfato impregnado com zinco, molibd?nio ou ambos e sua
aplica??o no estudo da remo??o de enxofre da gasolina atrav?s do processo de adsor??o,
utilizando uma gasolina modelo contendo iso-octano e tiofeno. Os adsorventes foram
caracterizados por difra??o de raios-X, an?lise termogravim?trica (ATG), fluoresc?ncia de
raios-X e microscopia eletr?nica de varredura (MEV). A ?rea espec?fica, volume e di?metro
de poros foram determinados pelo m?todo BET (Brunauer-Emmet-Teller) e m?todo t-plot. O
enxofre foi quantificado por analise elementar atrav?s do ANTEK 9000 NS. O Processo de
adsor??o foi avaliado em fun??o da varia??o da temperatura e da concentra??o inicial de
enxofre atrav?s das isotermas de adsor??o e de seus par?metros termodin?micos. Os
par?metros varia??o de entropia (ΔS), varia??o de entalpia (ΔH) e varia??o da energia livre de
Gibbs (ΔG) foram calculados pelo gr?fico de ln(K) versus 1/T. Os modelos de Langmuir,
Freundlich e Langmuir-Freundlich foram ajustados aos dados experimentais, tendo o ?ltimo
apresentado os melhores resultados. Os testes termodin?micos foram realizados nas
temperaturas de 30, 40, 50 ?C e constatou-se que o processo de adsor??o ? espont?neo e
exot?rmico. A cin?tica da adsor??o foi estudada por 24 horas e mostrou que a capacidade de
adsor??o para os adsorventes estudados segue a seguinte ordem: MoZnPO > MoPO > ZnPO >
AlPO. A capacidade m?xima de adsor??o foi 4,91 mg/g para o MoZnPO com uma efici?ncia
de adsor??o de 49%.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15910 |
| Date | 27 October 2011 |
| Creators | Gomes, Kalyanne Keyly Pereira |
| Contributors | CPF:08580772800, http://lattes.cnpq.br/2621516646153655, Paskocimas, Carlos Alberto, CPF:06296687877, http://lattes.cnpq.br/2365059843175411, Pereira, Camila Gambini, CPF:27111541812, http://lattes.cnpq.br/8055289812908100, Santos, Francisco Klebson Gomes dos, CPF:00779263405, http://lattes.cnpq.br/0273000754120553, Souza, Carlson Pereira de, Chiavone Filho, Osvaldo |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Engenharia Qu?mica, UFRN, BR, Pesquisa e Desenvolvimento de Tecnologias Regionais |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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